Carter Family picking, also known as the thumb brush, the Carter lick, the church lick, or the Carter scratch, is a style of fingerstyle guitar named after Maybelle Carter of the Carter Family. It is a distinctive style of rhythm guitar in which the melody is played on the bass strings, usually low E, A, and D while rhythm strumming continues above, on the treble strings, G, B, and high E. This often occurs during the break. The style bears similarity to the frailing style of banjo playing and is the rhythm Bill Monroe adapted for bluegrass music two decades later.

With this technique, Carter, who "was among the first" to use it, "helped to turn the guitar into a lead instrument". It is unclear how Maybelle developed her style.

The Carter scratch can be heard on the Carter Family's first recordings, from their first session in Bristol, Tennessee on August 1, 1927. Maybelle also learned a blues fingerpicking technique from Lesley Riddle, an African-American guitarist who met A. P. Carter in December 1928 and who used to frequent the Carter family household. Carter can be heard playing in this style on a number of Carter Family recordings. She also played slide guitar and, later, with a flat-pick.

The earliest origins of the Carter scratch style of guitar picking are unknown although it is rooted in the music of Appalachia and the American South. The style rose to prominence with the Carter Family, who became popular after their 1927 Bristol Sessions Recordings. Maybelle Carter both sang and provided instrumentation in the group, playing guitar, banjo, and autoharp. Maybelle learned to play the guitar at the age of thirteen by ear, never reading sheet music. She relied on the example of her brothers and mother to learn playing techniques and traditional folk songs. In the 1920s and 1930s, guitar was not yet a popular instrument in folk or country music. Maybelle recalled that "there weren't many guitar players around. I just played the way I wanted to, and that's it." Maybelle's guitar style has been characterized by archivist and musician Mike Seeger as having a "fluid, flowing, rhythmic sound, a way of playing the melody that… brought you in because it had rhythm and life to it." One student of Maybelle, Ruby Parker, commented on her guitar picking, stating that "She could make that guitar talk to you."

Among her many inspirations, Maybelle recalls that she was heavily influenced by traditional Baptist hymns as well as gospel music heard at Holiness revivals. Additionally, Maybelle listened to the radio and phonograph records and attended local music jams, "anything to get a little something different," she said. She credits Lesley Riddle, an African American musician, as a later influence on her style. Riddle first met Carter Family member A. P. Carter in the winter of 1928 after which he would accompany him on his song-collecting trips and was known for his ability to recall and reproduce tunes. For several years, Riddle and the Carters spent a lot of time together, learning new songs and perfecting their technique. Riddle remembered that for all his visits with the family, he rarely heard the Carters play for him: "They never sang for me. I'd have to do all the picking and singing." Instead, the Carters, Maybelle especially, attentively watched and listened to Riddle picking the blues for hours. But Riddle recollected that "You don't have to give Maybelle any lessons. You let her see you playing something, she'll get it. You better believe it." Riddle is credited with teaching Maybelle and the Carters one of their famous tunes, "Cannon Ball Blues."

Several songs highlight Maybelle's signature guitar style. "Single Girl, Married Girl", one of their most popular early recordings, illustrates the "innovation, versatility, and breadth" of the Carter Family's work. "Wildwood Flower" is perhaps the most famous song of the Carter's that includes Maybelle's unique style. Since its recording, it has become a key piece learned by countless fledgling guitarists.

Maybelle's daughter June Carter Cash remembered her mother's playing technique this way:

"She'd hook that right thumb under that big bass string, and just like magic the other fingers moved fast like a threshing machine, always on the right strings, and out came the lead notes and the accompaniment at the same time. The left hand worked in perfect timing, and the frets seemed to pull those nimble fingers to the very place where they were supposed to be, and the guitar rang clear and sweet with a mellow touch that made you know it was Maybelle playing the guitar."